The invention lies in the automotive art. Specifically, the invention concerns a device and method for securing a vehicle against unauthorized use.
A device for securing a vehicle against unauthorized use is known from German published patent application DE 195 08 370. There, a receiving antenna is mounted on the vehicle, via which signals sent from a central office can be received. A control unit is arranged in the vehicle, which stores use authorization information sent from the central office, at least temporarily. In other words, the vehicle being secured is equipped with a transmitting and receiving device to transmit data between the vehicle and a central office. Before release of the vehicle for utilization, bidirectional communication occurs between the vehicle and the central office, during which utilization restrictions are transmitted to the vehicle and stored in its anti-theft control unit. Utilization restriction can consist of stipulation of an admissible operating time or travel distance, or also the admissible number of startups of the vehicle or a maximum time interval of utilization independent of use. When the utilization restriction criteria are reached, the vehicle is shut down.
It is accordingly an object of the invention to provide a method and a device for securing a motor vehicle against unauthorized use, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which permits a refined allocation of utilization authorization to a vehicle.
With the foregoing and other objects in view there is provided, in accordance with the invention, a device for securing a motor vehicle against unauthorized use, wherein a plurality of keys are issued for the motor vehicle, comprising:
a receiver including antenna mounted on a motor vehicle for receiving signals from a central office;
a control unit disposed in the motor vehicle for storing use authorization information sent from the central office;
at least some vehicle keys issued for the motor vehicle being assigned an identifier different from identifiers assigned to others of the vehicle keys, and the control unit being programmed to:
query the identifier of a corresponding vehicle key upon an actuation thereof;
determine a use authorization information stored for the corresponding vehicle key; and
release a function requested by the corresponding key only when use authorization is present.
At least some, preferably all, keys issued for a vehicle can be selectively authorized or blocked in the invention. For example, if a vehicle key is lost or stolen, the invention permits selective blocking of this vehicle key, so that the vehicle can no longer be opened and/or started by this key. However, the other keys still remain authorized so that the vehicle can continue to be used with these other keys. The authorized user can therefore have access to the vehicle in the usual manner, but without the hazard of vehicle theft with the lost or stolen key. No mechanical interventions into the door lock system or ignition lock system are required. The necessary data to block the lost or stolen key can be sent to the vehicle by the central office, notified by the authorized user, and stored in its control unit.
In accordance with an added feature of the invention, the control unit comprises a memory storing use restrictions for one or more vehicle keys, and wherein the control unit no longer accepts a vehicle key as valid if a corresponding use restriction stipulated for the respective key is reached.
In accordance with an additional feature of the invention, the use restriction is defined as a maximum admissible number of uses of the corresponding key stored in the control unit, and each use of a vehicle key is selectively counted for the corresponding vehicle key, and a vehicle key is classified as unauthorized upon reaching the maximum admissible number of uses stipulated therefor.
In accordance with a further feature of the invention, the control unit contains a memory storing a time value for the corresponding vehicle key, and the control unit no longer accepts as valid a vehicle key a time value of which has been reached.
In accordance with again an added feature of the invention, the time value is stored as an admissible number of use days.
In accordance with again another feature of the invention, the data received by the control unit from the central office contain a vehicle key identifier notifying the control unit for which respective vehicle key the transmitted information, such as a maximum use number and/or a time value, is to be stored.
With the above and other objects in view there is also provided, in accordance with the invention, a method of blocking a motor vehicle against unauthorized use, which comprises:
selectively sending use authorization information for each of a plurality of vehicle keys of a motor vehicle from a central office to the motor vehicle, wherein each vehicle key is provided with its own identifier;
upon an actuation of a respective vehicle key, determining its identifier and querying the use authorization information stored for the respective vehicle key; and
accepting as valid only an authorized vehicle key.
As an alternative or in addition, it is thus also possible to stipulate, for each vehicle key, selectively determined use criteria, like maximum use frequency, use period or the like. As soon as a key reaches its utilization limit, it is no longer accepted by the vehicle control unit, i.e., no longer permits opening and/or starting of the vehicle until it is again classified as authorized via the central office.
Each of the keys issued for a vehicle can therefore be individualized with respect to its use authorization. However, it is not essential in all cases that all keys allocated to a specific vehicle be assigned mutually different utilization authorizations. It is also possible to classify the keys in groups with different utilization criteria and prescribe the same criteria for each key within a group. For example, this can be useful in larger companies, in which a certain vehicle is used by a number of persons, who are allocated to different person groups (for example, service employees/couriers/maintenance personnel). Moreover, it is possible to equip all keys issued for a specific vehicle initially with the same utilization rights and to adapt these utilization rights, as required, only according to certain situations. The information required for this is sent to the concerned vehicle by the central office (service provider) and stored in its control unit and/or transmitted to the corresponding key and recorded in it.
At least some, preferably all, keys prescribed for a certain vehicle contain their own identifier, which is queried by the control unit upon the actuation of the corresponding key (for opening the vehicle and/or operating the vehicle). The control unit preferably contains a memory, in which the utilization authorization and, optionally, the corresponding utilization parameters are stored for all admissible keys, for example, the admissible use frequency, etc. Upon an actuation of a key, the control unit queries the corresponding memory entry and decides from it whether the key is authorized or not. If it is not authorized, the control unit blocks opening of the vehicle and/or starting of the engine or another measure necessary for vehicle operation. However, if the key is recognized as authorized, key confirmation is accepted, i.e., the vehicle is opened or the engine started. If the maximum use frequency of the key is to be stipulated as utilization criterion, the thus far valid number of still admissible future uses is reduced by one and this value recorded in the control unit. As an alternative, the number of thus far executed key activations can also be counted and the current numerical value compared with a value stored in the control unit corresponding to the maximum use frequency stipulated for this key. If the latter value is reached, subsequent key activations are no longer accepted.
It is also possible to stipulate a use limit for a corresponding key in the form of a maximum time (for example, a total of 100 days"" use authorization).
As an alternative, it is also possible to store the use authorization of a corresponding key not in a control unit memory, but to record it directly in the key itself. In this case, an additional memory field is present in the key, in addition to its stored identifier, in which the information xe2x80x9cauthorizedxe2x80x9d or xe2x80x9cblockedxe2x80x9d is contained, preferably in coded form. Bidirectional communication between the control unit and the corresponding vehicle key is prescribed here, in which the control unit, during key use, not only queries its identification, but also the use authorization stored in it. Only when the use authorization reads xe2x80x9cauthorizedxe2x80x9d is vehicle utilization permitted. If, however, an order is fed to the control unit from the central office to classify a certain vehicle key in the future as xe2x80x9cunauthorizedxe2x80x9d, the control unit stores this information until the corresponding key is used. The control unit recognizes this use with reference to the key identifier and then transmits data to the key that cause rewriting of the corresponding key memory position from xe2x80x9cauthorizedxe2x80x9d to xe2x80x9cblockedxe2x80x9d. In the opposite case, when a previously blocked key is again treated as authorized, the control unit also transmits corresponding information to the key that causes rewriting of the corresponding key memory field to xe2x80x9cauthorizedxe2x80x9d. The data are fed from the control unit to the key, preferably coded, so that the hazard of unauthorized authorization of a blocked key is minimized. In this embodiment, the amount of information that must be stored in the control unit is significantly reduced, since the keys themselves contain the use authorization information.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in device and a method for securing a vehicle against unauthorized use, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.